1st + last = 100
2nd + 2nd last = 100
...
...
looks like I can form 50 such pairs
sum = 50(100) = 5000
use the same concept for the second question.
using gauess approach
1+2+3+4+... +99
1+3+5+7+...+101
1 answer
1+2+3+4+... +99
1+3+5+7+...+101
1 answer